miRNA作用机制研究进展

The Progress of mi RNA Action Mechanism

miRNA也称为microRNA,是长度21~24 nt的非编码RNA,由RNA聚合酶Ⅱ或Ⅲ转录,在细胞质内成熟,过去比较关注miRNA负调控基因表达的功能。其作用机制可分为抑制蛋白质在内质网上翻译的翻译抑制、介导对m RNA进行切割的转录本切割和切割转录本后的产物形成次生siRNA三种。最近,miRNA正调控基因表达的证据越来越多,其作用机制可分为有别于常规翻译的翻译激活和与靶基因上游增强子作用加强基因转录的转录增强。同时,还发现miRNA具有类激素的功能。本研究系统总结了目前miRNA的翻译抑制、转录本切割、次生siRNA形成、翻译激活、转录增强和类激素作用6种作用机制,并对miRNA作用系统网络研究策略及miRNA的实际应用进行了展望。

miRNAs,known as microRNA,were a kind of non-coding RNA with length 21~24 nt.They were transcribed by RNA polymeraseⅡorⅢand matured in cytoplasm.The researchers were focused on their negative regulation to genes expression function.The mechanisms of these can be divided into translation inhibition that some miRNAs inhibit the translation of proteins of the rough endoplasmic reticulum,transcripts cleavage that some miRNAs mediate the cleavage of target mRNA and biogenesis secondary siRNA from the products of transcripts cleavage.But more and more evidence indicated that miRNA can positively regulate genes expression also.The mechanisms of the positive regulations include translation activation that are different from the canonical translation and transcription activation that miRNA combination with the upstream enhancers of target genes activated the transcription of the genes.And some miRNAs trigger downstream signal pathway like hormones even.We summarized six action mechanism of miRNA:translation inhibition,transcripts cleavage,secondary si RNA biogenesis,translation activation,transcription activation and hormone like function comprehensively;we prospected the research and applications trends of miRNA finally.